The effects of restricted feeding on adrenal cortical activity in the immature domestic fowl

1. The effect of reducing food intake to 75% of the ad libitum intake was determined from hatching to 8 weeks in young Light Sussex chickens.

2. Restricted birds were lighter throughout the experiment.

3. Relative adrenal weight tended to be greater in restricted birds but the difference decreased with time.

4. There was no depletion of adrenal cholesterol: from week 5 there was a significantly greater amount in the adrenals of restricted birds.

5. After 1 week of restriction plasma corticosterone concentration was 73% greater than in controls. It decreased progressively, falling within the normal range at 5 weeks.

6. Restricted birds were hypoglycaemic from weeks 2 to 7 and hyper‐lipacidaemic throughout. A negative correlation between plasma glucose and free fatty acids was found.     

Effects of method of processing and chilling of Turkey carcasses on processing losses,water absorption and yields

1. The effects of wet or dry plucking, wet or dry evisceration procedures and method of chilling on processing losses and water uptake during chilling were studied using 19‐week‐old female large white turkeys.

2. Dry plucking increased weight loss due to plucking and eviscerating, and reduced chilled carcass yield.

3. Dry eviscerating increased carcass water uptake during chilling.

4. Pre‐chilling with running water increased carcass water uptake compared with chilling in ice and water alone.

5. Water uptake during chilling appeared to be increased by longer eviscerating time.     

The effects of trienbolone acetate implantation of Turkeys upon fluid balance and blood chemistry

1. The effects of implanting turkeys with trienbolone acetate (TA) upon fluid balance and blood chemistry were studied.

2. The Na and water contents of skeletal muscles were increased by TA treatment while K was unaltered.

3. The extracellular space expressed as a proportion of starved body weight was unaffected by TA implantation.

4. Plasma or serum concentrations of P, Ca, Mg, Na and K and activities of the enzymes aspartate aminotransferase [EC 2.6.1.1], creatine kinase [EG 2.7.3.2] and γ‐glutamyl transferase [EC 2.3.2.2] were not changed by TA treatment.

5. Packed cell volume was significantly increased by TA implantation after a delay of some 2 to 3 weeks while plasma protein concentrations were immediately decreased for a period of two weeks before nearly normal concentrations were obtained again.

6. Erythrocyte sedimentation rate was decreased by TA treatment, but serum protein electrophoretic pattern was unchanged.     

The importance of convection in the determination of the water vapour conductance of avian egg shells

1. It was confirmed that convection across the avian egg shell surface does not affect diffusive transport of water vapour through the shell.

2. Relative water vapour conductance, i.e. the ratio between the water vapour conductance as determined in a desiccator and the actual water vapour conductance, as well as relative humidity in the desiccator are influenced by the total rate of water loss of the eggs in the desiccator.

3. The total rate of water loss is influenced by the number of eggs in the batch, their average actual water vapour conductance, desiccator temperature and barometric pressure.

4. Therefore water vapour conductance is easily underestimated, in particular when determined in still air at a small surface area of desiccant.

5. All the above effects are considerably reduced by convection.

6. Further improvements in technique are suggested, particularly for practice where determinations have to be made for a relatively large batch of eggs.     

Effect of age and sex on the chemical composition of edible offal and blood from broilers

1. The effects of age and sex on the proximate composition and inorganic constituents in edible offal and whole blood from a commercial British broiler chicken strain were studied.

2. Although the protein content of all tissues varied with age, the only statistically significant effect was on the level of protein in the gizzard.

3. The moisture content of the gizzard was significantly affected by age and blood by age and sex.

4. The fat content of the gizzard was significantly affected by age, as was the effect of sex on the fat content of blood.

5. The ash contents of heart and gizzard were significantly affected by age.

6. The phosphorus contents of the gizzard, heart and liver were significantly affected by age, as were the chloride content of heart and the calcium content of the liver. Blood potassium was significantly affected by sex. Fluctuations in the contents of other elements are discussed.

7. The variability in organ composition is discussed with respect to the degree of trimming and preparation of the samples.     

Effects of high inclusion rates of salseed meal in the diet of chicks

1. Starter diets containing either maize or salseed meal to replace the maize were fed to chicks over a period of 2 weeks.

2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.

3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.

4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.

5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg.     

Influence of site and variety on starch,hemicellulose and cellulose composition of wheats and their digestibilities by adult cockerels

1. It has been shown that both the variety of wheat and the environment under which growth took place influenced the quantities of starch and cell wall carbohydrate contents of wheat.

2. The different varieties of wheat investigated contained different proportions of water‐soluble to water‐insoluble hemicelluloses.

3. By comparison of the arabinose to xylose ratios it was concluded that water‐soluble and insoluble arabinoxylans of wheat were branched to the same degree.

4. Starch from six wheat varieties grown in the U.K. was very well digested by adult cockerels and true metabolisable energy values of the wheats were high.

5. Small amounts of cell wall carbohydrates were digested by adult cockerels.     

Protein and energy metabolism in two lines of chickens selected for growth on high or low protein diets

1. Genetic adaptation was investigated in broilers selected for seven generations on a normal (A) or a low (B) protein diet.

2. Protein and energy metabolism were studied in males from these selected lines fed on a diet of intermediate protein content.

3. All selected birds retained more nitrogen than those studied 10 years previously.

4. There was no difference in nitrogen retention between groups, although relative growth rate of group B birds was higher.

5. Heat productions relative to gross energy intake were 0.38 (group B) and 045 (group A). Energy retentions relative to gross energy intake were 0.39 (group B) and 0.35 (group A); the difference being primarily due to higher fat retention in group B.

6. Using a common maintenance requirement for metabolisable energy, group B utilised metabolisable energy for growth (0.78) better than did group A (0.71).

7. At 53 d of age plasma glucose (10%) and insulin (50%) were higher in group B than in group A.     

A mathematical representation of the Ovulatory cycle of the domestic hen

1. The ovulatory cycle of the domestic hen (Gallus domesticus) was postulated to be the result of the interaction of two independent systems.

2. A circadian system was postulated to control the restriction of ovulation to an 8‐h period of the day under conventional 14 h light: 10 h dark regimes.

3. The final phase of follicular maturation was postulated to commence after ovulation of the preceding ovum in the hierarchy.

4. Ovulation was postulated to occur when a mature follicle was present in the ovary during the appropriate phase of the circadian‐linked system.

5. The predicted times of oviposition were within the standard error of the observed times of oviposition under 21‐, 24‐ and 28‐h photoschedules.

6. It was concluded that this hypothesis for the control of the ovulatory cycle of the hen is consistent with current knowledge.     

The occurrence of salmonellae during the rearing of broiler birds

1. The incidence of salmonellae was studied in two broiler houses at each of two commercial sites in an integrated commercial enterprise.

2. Salmonellae were not isolated from the empty, cleaned and fumigated houses and only on one occasion from the foodstuffs.

3. Salmonellae were isolated from the environment of the chicks and spasmodically from the litter, water troughs and dust.

4. The incidence of infection of the chicks did not influence the number of isolations of salmonellae from the environment of the birds during rearing.

5. Water in the water troughs rather than foodstuffs appeared to be the major oral route of infection or re‐infection of birds during rearing.     

Plumage loss in medium‐bodied hybrid hens: The effect of beak trimming and cage design

1. Plumage loss was assessed by visual scoring in 288, 78‐week‐old hens, housed as groups of four in battery cages, which differed in the design of the cage front and the position of the nipple drinkers.

2. Half the hens had undergone beak trimming at 18 weeks, but in many cases regrowth had occurred.

3. Plumage damage and loss was significantly reduced in beak‐trimmed birds compared with birds with normal beaks. Tier and cage design had no effect.

4. This finding supports the idea that feather pecking is the important factor in causing plumage damage, rather than abrasion.

5. A comparison between 64 birds in which beak regrowth had occurred, and 64 in which it remained truncated, showed that both groups had similar plumage scores.

6. It appears to be the beak‐trimming procedure which is important; subsequent regrowth being irrelevant.     

Effects of ageing and gonadal steroid hormones on prolagtin concentration in the anterior pituitary of the chicken

1. Effects of ageing and gonadal steroid hormones on pituitary prolactin (PRL) concentration in the chicken were investigated.

2. No difference was found in the qualitative electrophoretic patterns of the anterior pituitary homogenates at different ages and between the sexes.

3. Pituitary PRL concentrations in males were generally higher than in females.

4. Pituitary PRL concentrations in castrated immature cockerels were higher than in intact birds, while PRL concentration was depressed by the injection of testosterone propionate or oestradiol benzoate.

5. Prolactin concentration in intact immature cockerels was decreased by daily injection of testosterone or oestradiol for 3 weeks but not by injection of the hormones for 1 week.     

Water balance of Colostomised and non‐Colostomised hens at different ambient temperatures

1. The quantities of water gained and lost, and hence the total water balance, were determined in normal and colostomised White Leghorn laying hens at ambient temperatures of 5, 20 and 35 °G.

2. In both groups the water intake and water loss at all temperatures were well balanced.

3. Water to food ratios and water content of excreta of normal hens increased with increasing temperature.

4. The wetter excreta at 35 °C are caused by an increased urine production and not by an increased water passage through the alimentary tract.     

The presence of salmonellae during the rearing of Turkeys

1. The incidence of salmonellae was investigated in two batches of turkeys in the environmentally‐controlled houses and naturally ventilated pole‐barns of a commercial turkey enterprise.

2. The poults were free from contamination on arrival at the rearing house but were contaminated via the water supply from troughs which had been ineffectively fumigated.

3. Foodstuffs did not appear to be a source of contamination.

4. The spread of salmonellae in this turkey rearing enterprise was very similar to that in chicken rearing houses.     

Corticosterone and fat deposition in broiler chicks: Effect of injection time,breed, sex and age

1. Corticosterone (680 μg/kg body weight per day) given as six daily injections to 3‐ or 7‐week‐old chicks decreased weight gain, but increased food consumption, abdominal fat pad weight, skin dry matter, relative liver size and liver fat concentration.

2. Time of day of injection did not modify the response to corticosterone of 3‐week‐old chicks kept under natural daylight nor of 7‐week‐old broilers receiving additional illumination.

3. Pure White Rock chicks and Cornish x White Rock crossbred chicks responded similarly to corticosterone injections at 3 weeks of age.

4. Seven‐week‐old female birds treated with corticosterone had significantly larger abdominal fat pads than similarly treated males.

5. Corticosterone injection was more effective in increasing the proportion of liver fat in 7‐week‐old birds than in 3‐week‐old ?hicks.

6. The increased amount of abdominal and liver fat due to corticosterone injections administered at 3 weeks of age disappeared after 3 weeks, but growth depression was still evident.     

Selection for high specific gravity of eggs in a flock of Australorp hens

1. A realised heritability of 0.23 was obtained in an Australorp flock (S) selected for five generations for high egg specific gravity.

2. A comparison with an unselected control flock (C) over 50 weeks of lay in the final generation indicated a number of statistically significant correlated responses in commercially important traits in the S line in addition to the direct response of + 0.004 in specific gravity.

3. With an increase in specific gravity, there was a decrease of 3.4 in the percentage of soft‐shelled eggs laid.

4. The weight and albumen height of eggs measured within 1 hour of lay declined by 1.8 g and 2.1 Haugh units respectively.

5. There were reductions in the weight and albumen height losses of eggs stored over a 10‐d period (C 0.74, S 0.62 g and C 17.9, S 15.0 Haugh units respectively), so that at the end of this period the albumen heights in both lines were the same.

6. Average body weight and daily food intake were less by 0.28 kg and 7.5 g respectively.

7. Although there was no change in egg production, the average age at first egg was reduced by 11.3 d.     

Physical and chemical nature of eggs from six breeds of domestic fowl

1. The physical nature and chemical composition of the eggs from several breeds, White Leghorn, Rhode Island Red, Sussex, Maran, Dwarf Sussex and English Gamecock, have been studied.

2. The water content was highest in White Leghorn eggs, which were the heaviest.

3. Cholesterol content was similar in all eggs except for Dwarf Sussex in which it was less.

4. English Gamecock eggs contained a higher proportion of protein than those of the other breeds.

5. From the data presented, egg size, under similar conditions of feeding, does not determine the contents of components of the egg, but there are underlying genetic factors.     

Evaluation of bone strength,keel bone status,plumage condition and egg quality of two layer lines kept in small group housing systems

1. The aim of the present study was to determine the influence of large (54 or 60) and small (36 or 40) group sizes and tiers of the small group housing system “Eurovent German” on tibia and humerus bone breaking strength, keel bone status, plumage condition and egg quality for two commercial layer lines, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), at the same stocking density (890 or 830 cm²/bird).

2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.

3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.

4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.

5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.

6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.

7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.

8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.

9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups.     

Production traits of artificially and naturally hatched geese in intensive and free-range systems: I. Growth traits

1. This study investigated the effect of incubation type and production system on geese growth traits.

2. A total of 216 geese were either naturally (114) or artificially (102) hatched and reared in intensive or free-range production systems (4 replicates each) until 18 weeks of age.

3. Weights of naturally hatched goslings (NHG) were significantly higher than artificially hatched goslings (AHG) at 2 weeks (644 vs. 536 g); however, weights of AHG were significantly higher than NHG at both 6 weeks (3245 vs. 3010 g) and 18 weeks (5212 vs. 4353 g).

4. AHG had better feed conversion ratios (FCRs) than NHG (6.21 vs. 6.46 at 18 weeks). Feed consumption of naturally hatched geese was found higher in first 4 weeks when compared to artificially hatched geese and artificially hatched geese consumed more feed than naturally hatched geese after 8 weeks.

5. Production system had insignificant effects on feed consumption, FCRs, viability and mutilation rates.

6. Slipped wings were more frequent in NHG than AHG (8.32% vs. 1.68% at 6 weeks; 23.84% vs. 5.12% between 7 and 18 weeks) and in free-range production when compared to intensive production (17.88% vs. 11.08% over the course of the production period).

7. The study results indicate that both artificially and NHG can be reared in free-range production systems without any loss in performance and in deference to animal welfare.